Connecting lines and stations were closed and evacuated. Metropolitan Police later said the intention was to cause large-scale loss of life, but only the detonators of the bombs exploded, probably causing the popping sounds reported by witnesses, and only one minor injury was reported. The suspects fled the scenes after their bombs failed to explode.

On Friday 22 July, CCTV images of four suspects wanted in connection with the bombings were released.[2] Two of the men shown in these images were identified by police on Monday 25 July as Muktar Said Ibrahim and Yasin Hassan Omar.[3] The resultant manhunt was described by the Metropolitan police commissioner Sir Ian Blair as "the greatest operational challenge ever faced" by the Met.[4] During the manhunt, police misidentified Jean Charles de Menezes as one of the suspected bombers and shot and killed him.[5]

By 29 July, police had arrested all four of the main bombing suspects from 21 July attempted bombings. Yasin Hassan Omar was arrested by police on 27 July, in Birmingham. On 29 July, two more suspects were arrested in London. A fourth suspect, Osman Hussein, was arrested in Rome, Italy, and later extradited to the UK.[6][7] Police also arrested numerous other people in the course of their investigations.

On 9 July 2007, four defendants, Muktar Said Ibrahim, 29, Yasin Hassan Omar, 26, Ramzi Mohammed, 25, and Hussain Osman, 28, were found guilty of conspiracy to murder.[8] The four attempted bombers were each sentenced to life imprisonment, with a minimum of 40 years' imprisonment.[9]

In each case, only the detonator caps fired and the bombs themselves did not go off; this may have been due to the low quality hydrogen peroxide used in the devices, which had been obtained from a large number of easily available sources. The explosions were small—only about as powerful as a large firework—and no injuries were reported, although a person who suffered an asthma attack was counted as the incident's sole injury.[10]

Some eyewitnesses reported a "strange smell", described by some as resembling burning rubber, emanating from the Underground stations. Some early reports seem to be suggesting that the smell preceded the bang by several minutes. It appears that people on a train smelt a strange odour, and realised something was wrong. They ran from one carriage to another while the train was still moving and then heard an explosion behind them.

Eyewitnesses at the scenes reported seeing men running away from the site of the explosions, and there were unconfirmed suggestions that one of the bombers had been injured.

It was reported that one of the 7 July suspects, Jamal (Germaine) Lindsay, had bought £900 worth of perfumes immediately before the bombings, possibly to disguise the acrid smell of the decomposing explosives. Some witnesses reported seeing a white powder: TATP is a white crystalline powder. An eyewitness mentioned that as one of the explosions occurred there was a "smell of vinegar" which could be attributed to combustion byproducts of the explosive TATP.[11]

University College Hospital, near Warren Street, was cordoned off at 14:30 BST, reportedly by armed police. Eyewitnesses reported seeing three armed police officers entering the building.

Both CNN and The Times[12] reported that the armed police at University College Hospital were pursuing a suspected bomber who fled into the building following a chase on foot down Tottenham Court Road. Witnesses reported shots being fired as the man led police on the chase from Warren Street Underground station. Police say the "gunshots" may have actually been detonators going off.

An internal memo at the hospital told employees to look for a tall man with wires protruding from his clothing. The memo reportedly described the suspect as "a black male, possibly of Asian origin, about 6 ft 2 in (188 cm) tall, wearing a blue top with wires protruding from the rear of the top."[13] The BBC spoke to Prof Jim Ryan of UCH, who said he had not seen any such memo and dismissed the idea as "absolute rumour."[14] A BBC reporter, however, said that he had been given a copy of an email sent to staff asking them to look for the suspect.[15]

Later in the afternoon police said they had ended their armed operation at the hospital, but returned 30 minutes later. A Scotland Yard spokesman told the BBC: "We've got our armed deployment at UCH but we can't discuss it further."[16] There were conflicting reports on whether the redeployment was related to the bombings. CNN reported that sources told them police had returned to conduct a manhunt inside the building, but police said the deployment was unrelated to the explosions.

At 15:30, around two hours after the explosions, a major security alert occurred in Whitehall outside the Ministry of Defence during which a man was arrested by armed police. The man was ordered to lie on the pavement before being handcuffed and arrested, about 20 metres from Downing Street. He was also ordered to open his jacket and shirt before being taken by the police, presumably to allow police to see any hidden explosives that may have been on his person. He did not appear to be carrying any bags, and did not seem to be wearing a belt, although it was very hard for the reporter to see. The BBC reported (and television coverage showed) that he was wearing a small black backpack which the police had him remove before undoing his shirt.

Two other people were also arrested: one in the Whitehall area, and one near Tottenham Court Road, according to the BBC. But all were later released without any charges being brought against them.

According to Metropolitan Police Commissioner Sir Ian Blair, the two arrests in Whitehall were "totally unconnected" to the earlier explosions.

A security alert was declared, mid-afternoon, at St Albans railway station, north of London. The station was closed and the surrounding area evacuated following the discovery of an unattended backpack. A number 37 bus (Putney to Peckham) was also cordoned off after a suspect package was discovered.[17] These incidents are both believed to be bomb scares.

Police shot and killed a Brazilian man, Jean Charles de Menezes, at Stockwell Underground station shortly after 10:00 on 22 July. Officers had pursued de Menezes from a location under surveillance, believing him to be one of the men wanted for the attacks of the previous day. They apparently believed de Menezes, who was claimed to be wearing a heavy jacket – later shown to be an ordinary denim jacket – was a possible suicide bomber.

Police later confirmed he was not related to the bombing incidents and issued an apology, saying that "For somebody to lose their life in such circumstances is a tragedy and one that the Metropolitan Police Service regrets."[18]

Services on the Victoria line between Victoria and Brixton and on the Northern line between Kennington and Morden were suspended at the request of the police.[19][20]

Sky and BBC News reported that the East London Mosque on Whitechapel Road in Whitechapel had been surrounded by armed police and that residents were told to stay indoors. The mosque was evacuated at about 10:30 and searched. However, police confirmed that it was a bomb scare and the all-clear was given after just over an hour.[21]

Security alerts continued into the weekend, with major disruption to London's transport system.

On 23 July, a suspect package was found in bushes in Little Wormwood Scrubs, just north of White City and Shepherd's Bush. It was subjected to a controlled explosion and appears to have been a further bomb made to the same design as the others used on 21 July. This led to speculation that a fifth bomber might be at large.[22] Scotland Yard stated that they were looking for more than just the four men caught on CCTV,[23] and by 29 July five suspected bombers had been arrested.

Like other devices used on 21 July, the device was packed into a six-and-a-quarter-litre clear plastic food container with a white lid, manufactured by Delta of India, sold in about 100 outlets across the UK. The police made an appeal to retailers who may have sold five or more in the time period.[24]

It was immediately apparent that the explosions were the result of an attempted terrorist attack, but it was initially unclear whether the explosions were a serious attempt to repeat 7 July bombings or were merely a symbolic attack or hoax intended to cause panic rather than mass casualties. The explosives used by the bombers consisted of Chapatti flour powder mixed with liquid hydrogen peroxide,[25] detonated by a booster charge.[26] This was not the same explosive mixture used by the bombers in the 7/7 bombings two weeks earlier, which had used TATP. It was later confirmed that substantial improvised explosive devices capable of causing significant numbers of casualties had in fact been involved, but had failed to explode. The explosions were caused by detonators which failed to detonate the main explosive charge. Police later disclosed that some of the devices used had survived the explosions and were available for forensic investigation.[27]

Both sets of bombings involved three Underground trains and a bus; in both cases, rucksacks were involved; and in both cases, the three Underground explosions were roughly simultaneous while the bus explosion was an hour later. Moreover, in both cases, the four explosion locations were dispersed around central London in such a way that they could be reasonably said to have occurred "in the north, south, east, and west," recalling the wording of several Islamist manifestos.

It was later reported that three of the four devices were of similar size and weight to those used on 7 July, with the fourth being housed in a smaller plastic box; all were said to have used the same type of explosive.[28]

Late Thursday night, a group calling itself the Abu Hafs al-Masri Brigade, after a nickname for one of Osama bin Laden's lieutenants who was killed in a 2001 airstrike in Afghanistan, posted a statement claiming responsibility for the attempted bombings. The group vowed that the terror would continue as long as Europe's soldiers were in Iraq. The group also claimed responsibility for the 7 July 2005 London bombings, the 2004 Madrid train bombings, and the 2003 North America blackout. Experts doubt the legitimacy of the group, as security experts have discredited the claims of the Madrid attack, and investigators have ruled out sabotage as a cause of the blackout. In its statement, the group cited Rome, Amsterdam and Copenhagen as future targets. However, the group has made threats in the past that it has failed to carry out. The group has also previously falsely claimed responsibility for events that were the result of technical problems, such as the 2003 London blackout and Northeast Blackout of 2003.[29]

Several individuals were reported to have been arrested on 22 July in connection with the bombings, including one man in Stockwell—the area where the shooting incident took place—and another man at a Snow Hill railway station in the city of Birmingham who was soon released without charge. The former may be among the individuals seen running away from the scenes of the incidents who were caught on CCTV footage. Police released images of people they wished to question with regards to the attempted bombings captured from London transport CCTV cameras.

On 25 July, two of the suspects were named by police as Yasin Hassan Omar and Muktar Said Ibrahim (also known as Muktar Mohammed Said).[24] Yasin Hassan Omar is suspected of trying to detonate the device at Warren Street tube station and Muktar Said Ibrahim is suspected of trying to detonate the device on the bus.[30] The Home Office has stated that both men have legally been residents for at least ten years.[30]

On Wednesday 27 July, police arrested Omar in Birmingham.[31] A suspect package was found in the course of his arrest. Three further arrests were also made in Birmingham. This raid was raised because the caretaker of the area found around 10 large bottles of hair dye, which can be used in explosives, and he was suspicious so called a low level police contact.

Major police raids occurred in west London on 29 July. It has been reported that a further two of the pictured suspects, Muktar Said Ibrahim and Ramzi Mohammed, were arrested in the course of these raids, while the Shepherd's Bush suspect – Osman Hussain – was arrested in Rome that day.[32] The men arrested in London were apparently the suspects wanted in connection with the Oval tube and bus bombing attempts, and the man arrested in Rome is the Shepherd's Bush suspect.[33] A European Arrest Warrant for Osman Hussain was issued by the Metropolitan Police, and he was extradited to the UK where he was charged on 8 December 2005. In addition the suspected fifth bomber Whabi Mohammad, 22, the brother of Ramzi Mohammad, was also under arrest by 28 July.[34]

On 26 February 2008, a Tanzanian-born Muslim man who dubbed himself "Osama bin London" was found guilty of encouraging his followers to murder non-believers and of running violent Islamist training camps in Britain. Mohammed Hamid, 50, who came to England when he was five, was convicted along with three followers – Kibley da Costa, 25, Mohammed al-Figari, 45, and Kader Ahmed, 20 – whom the jury found guilty of attending the training camps. A fifth suspect, Atilla Ahmet, 43, who once boasted of being Al Qaeda's top figure in Europe, admitted three charges of soliciting murder at the start of the complex four-month trial at Woolwich Crown Court. The trial was closely watched in Britain as Hamid was accused of providing the inspiration for the men who tried to carry out suicide bombings on London's transport system on 21 July 2005.[36]

Muktar Said Ibrahim, Manfo Kwaku Asiedu, Hussein Osman, Yasin Hassan Omar, Ramzi Mohammed and Adel Yahya began trial in relation to the attacks of 21 July 2005 at Woolwich Crown Court on 15 January 2007. The case was anticipated to last for 'up to four months,'[37] but in fact the jury only retired to consider the verdict on 28 June 5½ months later.

On 9 July 2007, the jury found Muktar Said Ibrahim, Yasin Hassan Omar, Ramzi Mohammed, and Hussain Osman guilty of conspiracy to murder.[8]

In November 2007, Manfo Kwaku Asiedu admitted conspiracy to cause explosions while a charge of conspiracy to murder was dropped. Adel Yahya pleaded guilty to a lesser charge.[38]

April 2008 the court of appeal judges dismissed a challenge by Ibrahim, Omar, Mohammed and Osman to their convictions.[39]

December 2014 an appeal to the European Court of Human Rights lodged in 2008 by Ibrahim, Omar and Mohammed claiming that their rights were breached in the 'safety interviews' after their arrests was rejected.[40]

In the afternoon of 22 July, house raids were conducted on Harrow Road in West London (approximately a mile from Paddington railway station). The road was cordoned off by armed police and some eyewitnesses reported seeing a bomb-disabling robot.

On 25 July police announced that they had raided a property in north London.[2] The property was a council flat in Curtis House, Ladderswood Way, New Southgate in which Yasin Hassan Omar had been living since 1999. No arrests were made in the raid although two men have been arrested in the area. Later reports suggested that explosives may have been found at the raided address.[30]

Major raids were carried out by the police on 29 July in the Notting Hill and North Kensington areas of West London. Three people were arrested during these raids, including two of the suspects who were thought to have carried out the failed bombing attempt. (see Wikinews article).

On 26 July it was reported that police had seized a vehicle abandoned in East Finchley, north London. The BBC reported that the vehicle was a white VW Golf which was not owned by any of the suspects but which was thought to have been used by them.[30]

During the initial investigation in Rome, Hussain said he was motivated to participate in the attacks after viewing videos of war-torn Iraq. "I am against war," Osman said "I've marched in peace rallies and nobody listened to me. I never thought of killing people." He claimed that the bombs were never meant to detonate or kill anybody, only to draw attention to the Iraq war.[44]

Other news sources reported that the bombers watched videos of women and children killed in Iraq by British and American troops before embarking on their mission.[45] Some quoted him as
saying "Muktar showed us some DVDs with images of the war in Iraq, especially women and children killed by American and British soldiers," Hussain said, adding that they were not to talk about these videos with others.[45]

"There was a feeling of hatred and conviction that it was necessary to give signal—to do something." Hussain denied links with either the Al-Qaeda or the 7 July bombers.[citation needed]

Prime Minister Tony Blair, Home Secretary Charles Clarke, and other ministers and key officials from government and the emergency services attended a meeting in COBR. Blair interrupted a meeting with Prime Minister of AustraliaJohn Howard to attend a COBR meeting, although he and Howard later gave a joint news conference in response to the attacks on both the London Underground and Bethnal Green (Howard was also in Washington, D.C., at the time of the 11 September 2001 attacks.) Whitehall, the main artery serving the governmental district, was initially sealed off and evacuated, but was reopened at 14:45. It was subsequently closed again around 15:25 following an arrest and a bomb scare, both of which were fairly quickly resolved.

Sir Ian Blair, the Met police chief, described the incident as "serious" but said that there were "fewer injuries", caused by bombs that appeared to be "much smaller than those used on 7 July".

The police advised people to stay where they were and not travel unless absolutely necessary. However, people living within a 300 metre radius of the bomb sites were evacuated, due to worries about chemical agents being used. By about 16:00, however, Sir Ian Blair described the situation as "firmly under control" and urged London "to get ... moving again".

According to the Evening Standard, stranded commuters and evacuated locals in Shepherd's Bush held an impromptu street party during the evening of 21 July, in the vicinity of the crime scene, which lasted until the early morning. Music was provided by a peace activism group, and several photographs of this appeared in London's local press the following day.

Prime Minister John Howard condemned the attack on the London Underground and Bethnal Green stated that Australia stood by Britain and that people should "beware the minds of terrorists" during a press conference with Tony Blair.

^"London alerts: At-a-glance". (Timeline for 22 July 2005 at 15:31): BBC News. 29 July 2005. Archived from the original on 7 July 2015. Retrieved 7 July 2015. Metropolitan Police Commissioner Sir Ian Blair describes the investigation into the London bombings as the greatest operational challenge ever faced by the Met.